Processing Cavity Pump and an Associated Pump Device

ABSTRACT

A progressing cavity pump comprises a stator having an inlet end for coupling to a fluid-receiving casing, the pump including an anchor element suitable for fastening the inlet end of the stator on a stationary support, and said inlet end and said anchor element including locking means for locking them together in rotation.

FIELD OF THE INVENTION

The present invention lies in the field of positive displacement pumps of the eccentric screw pump type, also referred to as progressing cavity pumps, or Moineau pumps.

In particular, the present invention relates to a progressing cavity pump and to a pump device including such a pump.

BACKGROUND OF THE INVENTION

In conventional manner, a pump device comprises a progressing cavity pump or Moineau pump and a fluid-receiving casing. The pump comprises a stator and a helical rotor received in the stator. The casing contains an intermediate shaft having one end coupled to the rotor and having its other end coupled to an outlet shaft of a drive motor. The stator is clamped between two flanges by means of pull rods.

Under certain conditions of use, excessive levels of torque may be present, e.g. as can happen when the temperature is high and the stator swells. The stator may then be caused to rotate by the rotor. Consequently, the ends of the stator are damaged so that sealing is no longer provided between the stator and the casing.

OBJECT AND SUMMARY OF THE INVENTION

An object of the present invention is to prevent the stator from rotating and thus to avoid it being destroyed.

To this end, the invention provides a progressing cavity pump comprising a stator having an inlet end for coupling to a fluid-receiving casing; the pump including an anchor element having at least one leg and at least one clamping body; said leg being suitable for standing on and for being fastened to a stationary plane support; said clamping body being suitable for clamping the inlet end of the stator; and said inlet end and said clamping body including locking means for locking them together in rotation.

In particular embodiments, the progressing cavity pump includes one or more of the following characteristics:

A pump wherein the locking means comprise:

-   -   at least one stator portion in relief forming part of said inlet         end of the stator;     -   at least one clamping body forming part of the anchor element,         said clamping body being suitable for clamping at least a         portion of the inlet end of the stator; and     -   at least one anchor portion in relief forming part of the         clamping body; the anchor portion in relief being suitable for         co-operating in complementary manner with said stator portion in         relief.

A pump wherein the stator portion in relief and the anchor portion in relief are positioned in such a manner that when the anchor element is fastened to the stator and on the stationary support, the longitudinal axis of the first cell is substantially vertical.

A pump wherein the stator portion in relief is a recess.

A pump wherein the clamping body comprises at least one clamping arm and a separate part carried by the clamping arm, the anchor portion in relief being formed on the separate part.

A pump wherein the stator portion in relief is a portion of a groove having a rectilinear bottom, and wherein the separate part is an assembly rod suitable for being engaged in the groove portion; said assembly rod being fastened to the clamping arm.

A pump wherein the clamping body comprises at least two half-collars, and wherein the assembly rod is suitable for being engaged in through holes provided respectively in the half-collars; said assembly rod being provided at each of its ends with an axial locking element.

A pump wherein the separate part is a set screw suitable for coming into abutment against the stator portion in relief; said set screw being fastened to the clamping arm.

A pump wherein the stator portion in relief is a flat.

A pump wherein the anchor portion in relief is formed on the clamping body.

A pump wherein the stator possesses an outlet end for coupling to a fluid delivery duct, and wherein the outlet end possesses a smooth annular groove.

A pump wherein the stator possesses an outlet end for coupling to a fluid delivery duct, and wherein the pump further includes a fastener member suitable for fastening the inlet end or the outlet end to an end tube fitting; the fastener member including a pull rod provided with first and second fastener elements.

A pump wherein the first fastener element comprises an oblong key of longitudinal axis suitable for being engaged in a keyhole in the end tube fitting, the keyhole including at least one first setback having a longitudinal axis, the longitudinal axis of the key being perpendicular to the longitudinal axis of the first setback when the fastener member is fastened to the clamping body.

A pump wherein the second fastener element comprises a thread and a nut suitable for being screwed onto the thread; said nut being suitable for coming into abutment against the anchor element.

The invention also provides a pump device comprising:

-   -   a fluid reception casing; the casing including a keyhole;     -   a drive shaft housed in the casing, one end of the drive shaft         being designed to be coupled to a drive motor;     -   a progressing cavity pump in accordance with any of the         above-mentioned characteristics; the stator having an inlet end         coupled to the casing; one end of the rotor being coupled to the         other end of the drive shaft; and     -   a fluid delivery duct, the stator including an outlet end         coupled to the delivery duct.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood on reading the following description given purely by way of example and made with reference to the drawings, in which:

FIG. 1 is a perspective view of a pump device comprising a progressing cavity pump in the first embodiment of the invention;

FIG. 2 is a section view on a vertical plane of the pump device shown in FIG. 1;

FIG. 3 is a partially exploded perspective view of a portion of the stator and of an anchor element of the progressing cavity pump in the first embodiment of the invention;

FIG. 4 is a perspective view of a portion of the progressing cavity pump in the first embodiment of the invention, said pump portion being coupled to a casing;

FIG. 5 is a perspective view of a pull rod of the progressing cavity pump of the invention;

FIG. 6 is a perspective view of an end tube fitting of the casing of the pump device of the invention;

FIG. 7 is an enlarged view of the keyhole in the end tube fitting shown in FIG. 6;

FIG. 8 is a perspective view of the stator of the progressing cavity pump in the first embodiment of the invention;

FIG. 9 is a partially exploded perspective view of a portion of the progressing cavity pump in a second embodiment of the invention, said pump portion being coupled to a casing;

FIG. 10 is an enlarged view partially in section of a portion of the progressing cavity pump shown in FIG. 9;

FIG. 11 is a perspective view of the stator of the progressing cavity pump in the second embodiment of the invention;

FIG. 12 is a perspective view of a portion of the progressing cavity pump in a third embodiment of the invention; and

FIG. 13 is an enlarged view of a portion of FIG. 12.

MORE DETAILED DESCRIPTION

In the description below, terms such as “high”, “low”, “bottom”, “top”, “vertical”, and “horizontal” are defined relative to a pump device 1 of the invention when installed on a horizontal support, as shown in FIG. 1.

With reference to FIGS. 1 and 2, the pump device 1 of the invention comprises:

-   -   a progressing cavity pump 2 comprising a helical rotor 4         received in a helical cavity 6 of a stator 8;     -   a motor (not shown) suitable for driving the rotor 4, the motor         having an outlet shaft 12;     -   an intermediate flexible drive shaft 14 that is coupled at one         of its ends to the rotor 4 and that is set into rotation at its         other end by the outlet shaft 12;     -   a casing 20 that houses the intermediate drive shaft 14, the         casing 20 being secured in leaktight manner to an inlet end 21         of the stator 8, the casing 20 possessing a lateral opening 24         constituting the inlet (arrow 25) for the fluid that is to be         delivered by the pump device 1; and     -   a fluid delivery duct or pipe 22, secured in leaktight manner to         an outlet end 23 of the stator 8.

The stator 8 is made of a rigid material, e.g. such as a metal. Optionally it includes a resilient material such as rubber bonded to the inside face of a metal structure.

As shown in FIG. 3, the inlet end 21 of the stator 8 is provided with a neck 28 forming a first shoulder 29 relative to the outside surface 30 of the stator. An end tube fitting 26 of the casing 20, shown in FIG. 4, is engaged on the neck 28.

The inlet end 21 of the stator 8 is also provided with a groove 31 forming second and third shoulders 27 and 32 with the outside surface 30 of the stator.

According to the invention, the groove 31 has two stator portions in relief 33 suitable for co-operating with two anchor orifices in relief 34 of complementary shape for preventing the stator 8 from rotating relative to a stationary support 38 shown in FIGS. 1 and 2, by means of an anchor element 36.

By way of example, the stationary support 38 is constituted by the ground on which the pump device 1 is placed, or by any other plane surface carrying the pump device 1.

Each stator portion in relief 33 includes a setback or a projection. It forms an impression.

In the first embodiment of the invention shown in FIG. 3, each stator portion in relief 33 is constituted by a flat 40 extending over an angular section of the stator lying in the range 5° to 40°.

Preferably, the stator portion in relief 33 is positioned at a predefined angular position around the stator 8 such that when the anchor element 36 is fastened to the stator 8 and is on the stationary support 38, the first cell 39 extends vertically and the longitudinal axis of the first cell is preferably substantially vertical, as can be seen in FIG. 2.

Advantageously, this angular position of the stator 8 improves the suction capacity of the pump 2.

Advantageously, this angular position of the stator 8 reduces the number of air bubbles.

Advantageously, this angular position of the stator 8 improves efficiency.

Advantageously, this angular position of the stator 8 also improves the cleanability of the pump 2.

The anchor element 36 has two identical anchor parts 41 and 43 that are suitable for being fastened to each other. Each of the anchor parts 41, 43 has a leg 44, 46 for standing on the stationary support 38, a clamping arm 48, 50 secured to the leg 44, 46, and a separate part 52, 54 carried by the clamping arm 48, 50. Thus, the inlet end of the stator is locally fastened to the stationary plane support 38 by the anchor element 36.

The anchor parts 41 and 43 are fastened to each other by means of screws 56, 58 screwed into orifices 60, provided in the top and bottom portions of the clamping arms 48, 50. Nuts 57, 59 are screwed onto the free ends of the screws 56, 58 so as to block the screws axially.

In this embodiment of the invention, the clamping arms 48, 50 are constituted by two clamping half-collars. When the anchor parts 41, 43 are fastened to each other, the clamping half-collars 48, 50 and the separate parts 52, 54 form a clamping body suitable for clamping the stator 8.

The clamping body is positioned in the groove 31 of the stator. The second and third shoulders 27 and 32 hold the clamping body in the groove 31 and prevent any axial movement of the anchor element 36 under the effect of the vibration and the pressure forces generated by the rotor 4 rotating in the stator 8, as can be seen in FIG. 2.

In a variant, the clamping arms 48, 50 clamp onto a portion only of the stator.

In a variant, the clamping arms are constituted, for example, by a ring that is fitted with independent clamping elements or by rectilinear clamping arms.

In this embodiment, the separate part 52 comprises a flat spacer 64 having a central stud 68 on its outside face 66. The flat spacer 64 and the central stud 68 are suitable for engaging respectively one in a rectangular housing 70 and the other in a hole 72 formed in the clamping arm 48, 50.

The anchor portion in relief 34 is formed on the inside face 74 of the spacer 64. The anchor portion in relief 34 is constituted in this example by a plane face suitable for bearing against the flat 40 of the stator so as to prevent the stator from rotating by means of the legs 44, 46.

The separate part 54 is identical to the separate part 52.

Preferably, the spacer 64 possesses a main face of dimensions that are greater than or equal to the dimensions of the flat 40 of the stator.

In order to ensure that the anchor element 36 is stable, the legs 44, 46 are fitted with respective support feet 76, each provided at its end with a half-hole 78. When the anchor parts 41, 43 are fastened to each other, the support feet 76 of the legs 44 and 46 come into contact with each other and form a base that is designed to be held against the stationary support 38 by means of a fastener screw 80 screwed through the half-holes 78. When the anchor parts 41, 43 are fastened to each other, the legs 44, 46 are spaced apart from each other by a distance that is substantially less than the diameter of the clamping collar formed by the clamping arms 48, 50.

Each clamping arm 48, 50 also includes a tab 82 extending vertically, projecting from the body of the clamping arm 48, 50. This tab 82 forms a notch 84 for receiving a member for fastening the stator 8 to the end tube fitting 26 of the casing 20, as can be seen in FIG. 2.

With reference to FIGS. 4 to 7, the fastener member, referred to below as a pull rod 90, is in the form of a bent rod, for example. It is suitable for providing a rigid connection between a clamping arm 48 or 50 secured to the stator 8 and the casing 20 or the pipe 22 visible in FIG. 2.

In particular, the pull rod 90 comprises a first rod portion 89 referred to as a rectilinear rod portion, and a second rod portion 91 referred to as a bent rod portion.

The end of the bent rod portion 91 is provided with a constriction 92 that is terminated by a key 94. The key 94 is formed by a generally oblong head. The long axis A-A of the key 94, also referred to as its longitudinal axis, is parallel to the central axis B-B of the rectilinear rod portion 89.

The key 94 is suitable for being engaged in a keyhole 98 formed in a collar 100 of the casing 20 or fitted to the casing.

The keyhole 98 has a first setback 102 open in the outside face of the collar 100 and a second setback 104 open in the inside face of the collar 100 and in communication with the first setback 102.

The first setback 102 presents an oblong shape identical to the shape of the key 94. The long axis C-C of the first setback 102, also referred to as its longitudinal axis, is perpendicular to the axis D-D of the end tube fitting 26.

At least a portion of the second setback 104 is circular, of diameter that is not less than the longest diameter of the key 94. Since the second setback 104 presents a length longer than the first setback 102 in the direction of the axis D-D of the end tube fitting 26, faces of the second setback 104 form bearing faces 106, 108 for the key 94. These bearing faces 106, 108 are located on either side of the longitudinal axis C-C of the first setback 102.

The edge face of the stator 8 is coated in an elastomer and is suitable for bearing against a shoulder 109 formed on the inside face of the end tube fitting of the casing 20 when the stator is assembled to the casing 20 so as to provide sealing therebetween.

With reference to FIGS. 4 and 5, a screw thread 110 is formed on the rectilinear rod portion 89 of the pull rod 90. This screw thread 110 is suitable for receiving a washer 114 and a nut 116. When the pull rod 90 is fastened to the anchor element 36, the washer 114 comes into abutment against the tab 82 and against the side face of the clamping arm 48. The clamping arm 48 is in abutment against the second shoulder 27.

As can be seen in FIG. 1, the anchor element 36 may be mounted on the inlet end 21 and also on the outlet end 23 of the stator 8.

When mounted on the inlet end, the pull rod 90 is suitable for pulling the end tube fitting 26 of the casing 20 against the inlet end 21 of the stator.

When mounted on the outlet end, the pull rod 90 is suitable for pulling the end tube fitting 115 of the pipe 22 against the outlet end 23 of the stator.

As can be seen in FIGS. 1 and 4 to 7, when the pull rod 90 is to be fastened to the end tube fitting 26 or 115, the key 94 is initially inserted into the first setback 102 and then into the second setback 104. The longitudinal axis A-A of the key 94 is then parallel to the longitudinal axis C-C of the first setback 102. Thereafter, the pull rod 90 is turned through an angle of 90° so that the longitudinal axis A-A of the key 94 is perpendicular to the longitudinal axis C-C of the first setback 102. A shoulder 96 formed between the constriction 92 and the key 94 is then in contact with the bearing faces 106, 108. The key 94 is then locked in the keyhole 98. Finally, the nut 116 is screwed onto the rectilinear rod portion 89 until the washer 114 comes into abutment against the tab 82 and against the side face of the clamping arm 48.

In a variant, the pull rod 90 is a rectilinear rod. Under such circumstances, it is fastened in a keyhole formed in a projection that is formed on the collar 100 of the casing 20.

With reference to FIGS. 3 and 8, the outlet end 23 of the stator is similar to the inlet end 21 of the stator. Identical elements of these ends are given the same references and they are not described a second time.

Unlike the groove 31 at the inlet end 21, the groove 118 formed at the outlet end 23 is a smooth annular groove. In other words, it does not have a stator portion in relief 33. An anchor element 36 similar to the anchor element shown in FIG. 3 is mounted in the groove 118. This anchor element 36 does not include the separate parts 52, 54.

When fastened to the groove 118 without the separate parts 52, 54, the anchor element 36 performs only a function of supporting the stator 8 and a function of engaging the pipe 22. It does not serve to prevent the stator from rotating or to index the position of the stator 8 relative to the position of a cell of the rotor 4.

In a variant, the anchor element 36 has a single tab 82 and a single pull rod 90 disposed on a clamping arm 48, on one side only of the stator 8. In a variant, the anchor element 36 has a plurality of tabs 82 and a plurality of pull rods 90 disposed on a clamping arm 48.

In a variant, the stator 8 has a single flat 40, and a single clamping arm 48, 50 is provided with a separate part 52.

In a variant, the flats 40 are formed directly on the clamping arms 48, 50. Under such circumstances, the anchor element 36 does not have separate parts 52, 54.

In a variant, at least a segment of the stator is of octagonal shape and the clamping arm is of complementary shape.

The progressing cavity pump 2 in the second embodiment of the invention is described below with reference to FIGS. 9 to 11.

This pump 2 comprises a stator 120 having an inlet end 122 and an outlet end 124, each suitable for receiving an anchor element 128.

The inlet end 122 is provided with a neck 126 on which the end tube fitting 26 of the casing 20 is engaged, as can be seen in FIG. 1. The neck 126 forms a shoulder relative to the outside surface 130 of the stator.

In the second embodiment of the invention, the stator portion in relief 33 is a portion of the groove 132. This groove portion 132 extends over an angular section of the stator 120 lying in the range 5° to 40°. It presents a rectilinear bottom.

The anchor element 128 is similar to the anchor element 36 of the first embodiment of the invention. Elements that are identical in these anchor elements are given the same references and they are not described a second time.

The anchor element 128 includes a separate part 52 with the anchor portion in relief 34 formed thereon.

In this embodiment of the invention, the separate part 52 is an assembly rod 134 suitable for being engaged in through holes 136, 138 provided in the free ends of the clamping arms 48, 50. The assembly rod 134 is provided at one of its ends with a head 140 and at its other end with a nut 142 that is screwed onto a thread so as to prevent the assembly rod 134 from moving axially in the through holes 136, 138.

The anchor element 128 may also be fitted with pull rods 90 that are not shown in FIG. 9.

With reference to FIG. 11, the outlet end 124 of the stator 120 also has a neck 126 on which the end tube fitting 115 of the pipe 22 is engaged, as can be seen in FIG. 1. An annular groove 140 is machined around the stator 120 taking the place of the anchor portion in relief 34. The anchor element 128 is suitable for being fastened in the annular groove 140 so that the assembly rod 134 passes through the groove 140.

The clamping arms 48, 50 are positioned in the groove 140 of the stator. The shoulders formed on the groove portion 132 hold the clamping arms in the groove 140 and prevent any axial movement of the anchor element 128 under the effect of the vibration and pressure forces generated by the rotor 4 rotating in the stator 8, as can be seen in FIG. 2.

As for the first embodiment of the invention, since the groove 140 is annular, when the anchor element 128 is fastened to the outlet end 124 of the stator 120 it serves solely to carry the stator 120 and to engage the pipe 22 without preventing the stator from rotating and without indexing the angular position of the stator 8.

A progressing cavity pump 2 in the third embodiment of the invention is shown in FIGS. 12 and 13.

The stator 8 of this pump 2 is identical to the stator of the pump in the second embodiment of the invention as shown in FIG. 8. The anchor element 142 of this third embodiment of the invention is similar to the anchor element 36 in the first embodiment of the invention. Elements that are identical in these anchor elements are given the same references and they are not described a second time.

Each tab 82 is pierced by a through hole 88 of axis perpendicular to the axes of the clamping arms 48, 50 and placed in register with the hole 72. The hole 72 is a through hole and it is tapped.

The separate parts 52, 54 as can be seen in FIG. 3 are not constituted by spacers, but rather by set screws 144, preferably having flat ends, that are inserted in the through holes 88 of the tabs 82 and that are screwed into the tapped holes 72. The set screws 144 are suitable for coming into abutment against the flats 40 of the stator in order to prevent the stator from rotating.

The flat end of each set screw 144 co-operates with the flat 40 of the stator, as can be seen in FIG. 3. This flat end forms the anchor portion in relief 34.

In a variant, each set screw presents a pointed end suitable for co-operating with an orifice in the stator.

In a variant, the anchor element has only one tab 82 and only one set screw 144 fastened on only one side of the stator. In a variant, the anchor element has a plurality of tabs 82 and a plurality of set screws 144.

In a variant, the stator 8 has a flat 40, a spacer 64 without a central stud 68 mounted in the housing 70, and a set screw 144 screwed into the tapped hole 72. The set screw 144 then constitutes a clamping element of the spacer. The plane face of the spacer then forms the anchor portion in relief 34.

In a variant, the anchor elements in the three embodiments comprise “conventional” fastener members, e.g. pull rods fastened to the motor casing or to the motor and gearbox.

Advantageously, the pull rod 90 and the tab 82 are mounted on an anchor element 128, 142 in the second and third embodiments.

Advantageously, the fastenings both between the stator and the pipe and between the stator and the casing are easily dismantled by partially unscrewing the nuts 116 and tilting the pull rods 90 through an angle of 90°.

Advantageously, the pump of the invention includes means for orienting the first cell of the stator situated beside the casing and means for preventing the stator from rotating beside the casing. 

1. A progressing cavity pump comprising a stator having an inlet end for coupling to a fluid-receiving casing; the pump including an anchor element having at least one leg and at least one clamping body; said leg being suitable for standing on and for being fastened to a stationary plane support; said clamping body being suitable for clamping the inlet end of the stator; and said inlet end and said clamping body including locking means for locking them together in rotation.
 2. A pump according to claim 1, wherein the locking means comprise: at least one stator portion in relief forming part of said inlet end of the stator; and at least one anchor portion in relief forming part of the clamping body; the anchor portion in relief being suitable for co-operating in complementary manner with said stator portion in relief.
 3. A pump according to claim 1, wherein the stator portion in relief and the anchor portion in relief are positioned in such a manner that when the anchor element is fastened to the stator and on the stationary support, the longitudinal axis of the first cell is substantially vertical.
 4. A pump according to claim 1, wherein the stator portion in relief is a recess.
 5. A pump according to claim 2, wherein the clamping body comprises at least one clamping arm and a separate part carried by the clamping arm, the anchor portion in relief being formed on the separate part.
 6. A pump according to claim 5, wherein the stator portion in relief is a portion of a groove having a rectilinear bottom, and wherein the separate part is an assembly rod suitable for being engaged in the groove portion; said assembly rod being fastened to the clamping arm.
 7. A pump according to claim 6, wherein the clamping body comprises at least two half-collars, and wherein the assembly rod is suitable for being engaged in through holes provided respectively in the half-collars; said assembly rod being provided at each of its ends with an axial locking element.
 8. A pump according to claim 5, wherein the separate part is a set screw suitable for coming into abutment against the stator portion in relief; said set screw being fastened to the clamping arm.
 9. A pump according to claim 2, wherein the stator portion in relief is a flat and wherein the separate part is a set screw suitable for coming into abutment against the stator portion in relief; said set screw being fastened to the clamping arm.
 10. A pump according to claim 2, wherein the anchor portion in relief is formed on the clamping body, and wherein the stator portion in relief is a flat.
 11. A pump according to claim 1, wherein the stator possesses an outlet end for coupling to a fluid delivery duct, and wherein the outlet end possesses a smooth annular groove.
 12. A pump according to claim 1, wherein the stator possesses an outlet end for coupling to a fluid delivery duct, and wherein the pump further includes a fastener member suitable for fastening the inlet end or the outlet end to an end tube fitting; the fastener member including a pull rod provided with first and second fastener elements.
 13. A pump according to claim 12, wherein the first fastener element comprises an oblong key of longitudinal axis suitable for being engaged in a keyhole in the end tube fitting, the keyhole including at least one first setback having a longitudinal axis, the longitudinal axis of the key being perpendicular to the longitudinal axis of the first setback when the fastener member is fastened to the clamping body.
 14. A pump according to claim 12, wherein the second fastener element comprises a thread and a nut suitable for being screwed onto the thread; said nut being suitable for coming into abutment against the anchor element.
 15. A pump device comprising: a fluid reception casing; the casing including a keyhole; a drive shaft housed in the casing, one end of the drive shaft being designed to be coupled to a drive motor; a progressing cavity pump according to claim 1; the stator having an inlet end coupled to the casing; one end of the rotor being coupled to the other end of the drive shaft; and a fluid delivery duct, the stator including an outlet end coupled to the delivery duct. 